Apparatus for connecting electrical units to a test circuit



July 20, 1 965 P. w. FREUND ETAL 3,196,238

APPARATUS FOR CONNECTING ELECTRICAL UNITS TO A TEST CIRCUIT Filed July3, 1963 2 Sheets-Sheet 1 iTTU/g/gg y 1965 P. w. FREUND ETAL 3,196,238 QAPPARATUS FOR CONNECTING ELECTRICAL UNITS TO A TEST CIRCUIT Filed July3, 1963 2 Sheets-Sheet 2- former under test.

United States Patent York Filed July 3, 1963, Ser. No. 292,671 5 Claims.(Cl. 200-153) This invention relates in general to an apparatus forconnecting electrical units to a test circuit and, more particularly, tosuch as apparatus for accurately and rapidly connecting electrical unitsto a test circuit with uniform contact pressure' With certain electricalunits, as for example a transformer used in a submarine cable repeater,high performance standards are essential. One important electricalparameter which can affect the performance of a transformer is thevarious capacitances associated with the windings thereof. In order todetermine whether or not a transformer has acceptable values ofcapacitance, test circuit measurements are required. When precisemeasurements are required, each transformer tested should beconsistently positioned relative to and connected with uniform pressureagainst the contacts of the electrical measuring circuit. If suchprecautions are not taken,

i.e., if some transformers are connected or are held differently thanothers, as would occur in a manual operation, the measured readingobtained may not be indicative of the transformers true value or valuesof capacitance.

For these reasons, an apparatus is needed for rapidly measuring thecapacitance of transformers and the like, and which can be operated bydifferent and unskilled workers without affecting the desired manner inwhich successive electrical connections are made to the test circuit.

Accordingly, one object of this invention is to provide an apparatus foraccurately and rapidly connecting electrical units to a test circuit.

Another object is to provide an apparatus for connecting electricalunits to a test circuit wherein the electrical units are connected withuniform pressure to the contacts of the test circuit.

According to these and other objects of the invention, a slidablecarriage supports a pair of spring-biased jaws. The initial movement ofa hand lever closes these jaws with a predetermined pressure about thecore of the trans- Continued movement of the handle slides the carriageon which the jaws are mounted to a position at which the transformerterminals are connected has a driving section which transmits motion tothe carriage through a driving gear, and has a locking section toprevent movement of the driven gear at times when the same lever isperforming other operations.

Stops are provided on the lever so that the transformer leads cannot beforced into the test prongs with excessive pressure, regardless of themanner in which the operator moves the handle. Also, since the body ofthe transformer is electrically contacted and supported by the jaws inaccordance with the pressure exerted by the jaw springs, the resultantforce applied by the jaws against the unit is similarly beyond thecontrol of the operator.

The apparatus as embodied herein thus assures accurate gripping of thetransformer core and locks the slide in a fixed position during testingto achieve the degree of reliability required for testing highperformance transformers, and the like.

Other objects, features and advantages will become ice more apparentfrom the following detailed description when considered in conjunctionwith the accompanying drawings, wherein:

FIG. 1 is a side elevation of the apparatus showing the handle in itsinitial position and after approximately 30 of travel;

FIG. 2 is an isometric view of the apparatus showing the slidablecarriage with the leads of the electrical unit to be measured connectedto conductive prongs of the test circuit; and

FIG. 3 is an isometric view of the cam assembly.

Referring now to the drawings and more particularly to FIG. 1 thereof,there is shown a carriage 11 mounted on a slide 12 which is guided alonga linear path by supports 13 secured to the base 14. Horizontallydisposed within the carriage is a pair of jaws 17 with mutually opposedconcave surfaces 1?. These jaws are biased toward each other by twovertically disposed pairs of springs 16. Separate guide rods 18 affixedto the carriage are used to support the respective springs 16. Adifferent pair of spring-biased levers 21 are in slidable contact witheach of the mutually opposed and protruding end sec tions 15 of the jaws17, best seen in FIG. 2. A different spring 22 serves to pull each pairof levers 21 together.

Mounted on a common shaft 23 are a pair of cams 24, each positionedintermediate a different pair of the levers 21. The shaft 23 isjournaled within a frame 26 mounted on the base 14.

In accordance with one aspect of the invention, the jaws 17 are openedand closed upon the electrical unit being measured with uniform pressureand are moved a precise, horizontal distance to a terminal mount 37 bymeans of a unique double section cam assembly 27 which drives a rack 31and gear 29 associated with the carriage 11.

Considered more specifically, the cam assembly together with anoperating handle 28 are mounted on the shaft 23. As best seen inFIG. 3,the cam assembly includes a cam plate 25 which has a slot 34 therein. Apin 36, oriented parallel to the shaft 23, is supported at one end bythe cam plate 25 and at the other end by a tapered member 30 which isalso afiixed to the shaft 23. The gear 29, journaled within the frame26, operates in conjunction with the rack 31. A pin 32 and a slot 33 arelocated on the gear 29. The relationship and functions of the variousslots and pins associated with the cam assembly 27 and gear 29 will bedescribed in greater detail in connection with a discussion of the modeof operation of the apparatus hereinbelow.

Secured to the base 14 is a terminal mounting fixture 37 for supportingconductive prongs 38. As shown in FIG. 1, an adjustable stop 39 preventstravel of the handle 28 below its initial position A and a pin 41secured to the hub of the handle 28 prevents travel of the handle beyondits opposite extreme position C by striking stop 42.

To operate, the handle 28 is placed in position A so that it restsagainst :the stop 39. When in this position, the carriage 11 iscompletely retracted from the fixed mounting fixture 37. Also at theinitial position A, the gear pin 32 is located at the innermost andclosed end of slot 34 of the cam plate 25 (FIG. 3). Approximately 30 ofupward angular movement places the handle 28 at position B. During themovement of the handle 28 through this sector, the pair of cams 24 arerotated sufiicientiy to permit both pairs of levers 21 to close by theforce exerted thereon by the springs 22. This, in turn, permits the jaws17 to move together by the force of the springs 16 exerted thereon so asto press against the body of the electrical unit (shown in phantom linesin FIGS. 1 and 2) being tested. The jaws 17 thus both physically holdthe unit and electrically contact the units body. Throughout the entiresector A-B of movement of the handle 28, the gear pin 32 remains withinthe cam plate slot 34, thereby preventing any rotational movement of thegear 29.

Once the handle 28 is moved upwardly beyond position B, the cam pin 36,best seen in FIG. 3, enters the gear slot 33 and the gear pin 32simultaneously leaves the cam slot 34. In this way, the gear 29 isunlocked to permit the pin 36 in sliding association with the slot 33 torotate the gear 29 and drive the rack 31. Movement of the rack 31 slidesthe carriage 11 forward so that the leads of successive electrical unitsconnect the conductive prongs 38 monuted on the test fixture at the samepoints and with the same force exerted thereag airrst. Movement of thecarriage 11 also results in the jaws 17 withdrawing from the levers 21.This permits the pair of cams 24 to rotate without effecting the closedposition of the jaws. Approximately 75 of angular movement of the handle28 is required between position B, where the jaws are closed, andposition C where the carriage has been moved adjacent the conductiveprongs 38.

At the conclusion of an electrical test, the handle 28 is pulledbackwards from position C towards position A. Such movement initiallyslides the carriage 11 away from the conductive prongs 38 andsubsequently causes the jaws 17 to open. This permits the testedelectrical unit to be removed and a new one inserted for a subsequenttest.

It is to be understood that the above described embodiment is simplyillustrative of the application of the principles of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of this invention and fallwithin the spirit and scope thereof.

What is claimed is:

1. An apparatus for connecting a succession of electrical units to acircuit rapidly and with consistent con tact pressure, comprising:

a supporting base,

a slidable carriage mounted on said supporting base,

alpair of jaws mounted on said slidable carriage for holding the body ofan electrical unit, means mounted on said base for supporting aplurality of conductive prongs in predetermined spaced relation tocoincide with and contact the respective leads of the electrical unitheld by the pair of jaws as the slidable carriage reaches apredetermined position adjacent the conductive prongs, single-motionactuating means for initiallyopening and closing said jaws whilemaintaining the slidable carriage locked in a fixed position and forsubsequently sliding said carriage to said predetermined positionadjacent the electrical prongs while maintaining said jaws in a closedposition against said electrical unit with uniform pressure, and stopmeans to determine the contact pressure between leads of the electricalunit and the conductive prongs.

2. An apparatus according to claim 1 wherein said single motionactuating means includes:

a rotatable shaft, 7

a handle mounted on the shaft,

a cam assembly mounted on the shaft, said cam assembly having a pinmounted thereon and a slot located therein, V V

a rack for actuating said slidable carriage, and

a gear with a slot therein for driving said rack, said cam assembly pinslidably engaging the slot of said gear during one portion of arcuatemovement of said handle to prevent rotation of said gear, andsaid gearhaving a pin mounted thereon which slidably engages the Cam assemblyslot to actuate said gear during a separate portion of arcuate movementof said handle. 7 3. An apparatus for connecting a transformer to a testcircuit with a single movement of a handle comprising: a supportingbase, 7

a slidable carriage mounted on said base,

a pair of movable jaws mounted on said slidable carriage for holding thetransformer and electrically contacting the core of the transformer,

spring means for normally biasing said jaws toward each other,

a fixed mounting in the path of movement of the slidable carriage, a

conductive prongs fastened to said fixed mounting to receive therespective leads of the transformer held by the spring-loaded jaws asthe slidable carriage moves toward the fixed mounting,

spring-biased lever means for actuating said jaws,

a shaft rotatably positioned on said base,

a handle mounted on said shaft,

cam means affixed to said shaft for simultaneously actuating the levermeans,

a rack slidably guided on said base for driving said carriage,

a gear rotatably mounted on said base for driving said rack,

a cam assmbly mounted on said shaft to lock the gear during one sectorof movement of the handle while the cam means rotates to actuate thejaws, and to actuate the slidable carriage through the rack and gearduring another sector of movement of the handle to connect the leads ofthe transformers to conductive prongs, and e stop means to determine thecontact pressure applied by said handle between'the leads of theelectrical unit and the conductive pron gs.

4. An apparatus according to claim 3 wherein:

the cam assembly includes a pin mounted thereon and a slot locatedtherein wherein,

the gear includes a slot therein for driving said rack, said camassembly pin slidably engaging the slot of said gear during one portionof arcuate movement of said handle to prevent rotation of said gear, and

wherein, e

said gear includes a pin mounted thereon which slidably engages the camassembly ,slot to actuate said gear during a separate portion of arcuatemovement of said handle.

5. A handle-operated locking and driving mechanism comprising: 1

a supporting base,

a rotatable shaft positioned on said supporting base,

a handle mounted on said shaft,

a cam assembly mounted on said shaft, said cam assembly having a pinmounted thereon and a slot located therein,

a rack mounted on said base for driving any desired movable apparatusconnected thereto, and

a gear with a slot therein for driving said rack, said cam assembly pinslidably engaging the slot of: said gear during one portion of arcuatemovement of said handle to prevent movement of said gear, said gearfurther having a pin mounted thereon which slidably engages'the camassembly'slot to actuate said gear during another portion of arcuatemovement of said handle.

' No references cited:

ROBERT K. S CHAEFER, Acting Primary Examinen

1. AN APPARATUS FOR CONNECTING A SUCCESSION OF ELECTRICAL UNITS TO ACIRCUIT RAPIDLY AND WITH CONSISTENT CONTACT PRESSURE, COMPRISING: ASUPPORT BASE, A SLIDABLE CARRIAGE MOUNTED ON SAID SUPPORTING BASE, APAIR OF JAWS MOUNTED ON SAID SLIDABLE CARRIAGE FOR HOLDING THE BODY OFAN ELECTRICAL UNIT, MEANS MOUNTED ON SAID BASE FOR SUPPORTING APLURALITY OF CONDUCTIVE PRONGS IN A PREDETERMINED SPACED RELATION TOCOINCIDE WITH AND CONTACT THE RESPECTIVE LEADS OF THE ELECTRICAL UNITHELD BY THE PAID OF JAWS AS THE SLIDABLE CARRIAGE REACHES APREDETERMINED POSITION ADJACENT THE CONDUCTIVE PRONGS, SINGLE-MOTIONACTUATING MEANS FOR INITIALLY OPENING AND CLOSING SAID JAW WHILEMAINTAINING THE SLIDABLE CARRIAGE LOCKED IN A FIXED POSITION AND FORSUBSEQUENTLY SLIDING SAID CARRIAGE TO SAID PREDETERMINED POSITIONADJACENT THE ELECTIRCAL PRONGS WHILE MAINTAINING SAID JAWS IN A CLOSEDPOSITION AGAINST SAID ELECTRICAL UNIT WITH UNIFORM PRESSURE, AND STOPMEANS TO DETERMINED THE CONTACT PRESSURE BETWEEN LEADS OF THE ELECTRICALUNIT AND THE CONDUCTIVE PRONGS.